An explorative, biomechanical analysis of spine motion during out-of-hospital extrication procedures

David Häske, Lars Schier, Jeronimo O N Weerts, Berthold Groß, Adrian Rittmann, Paul A Grützner, Matthias Münzberg, Michael Kreinest

Injury 2020 Feb;51(2):185-192

Objectives: The extrication of patients following a road traffic collision is among the basic procedures in emergency medicine. Thus, extrication is a frequently performed procedure by most of the emergency medical services worldwide. The appropriate extrication procedure depends on the patient's current condition and accompanying injuries. A rapid extrication should be performed within a few minutes, and the cervical spine (at least) should be immobilized. To our knowledge, the scientific literature and current guidelines do not offer detailed recommendations on the extrication of injured patients. Thus, the aim of the current study is to compare the effectiveness of spinal stabilization during various out-of-hospital extrication procedures.

Methods: This is an explorative, biomechanical analysis of spine motion during different extrication procedures on an example patient. Movement of the cervical spine was measured using a wireless human motion tracker. Movement of the thoracic and lumbar spine was quantified with 12 strain gauge sensors, which were positioned paravertebrally on both sites along the thoracic and lumbar spine. To interpret angular movement, a motionscore was developed based on newly defined axioms on the biomechanics of the injured spine.

Results: Self-extrication showed the least spinal movement (overall motionscore sum = 667). Movement in the cervical spine could further be reduced by applying a cervical collar. The extrication by a rescue boa showed comparable results in overall spinal movement compared to the traditional extrication via spineboard (overall motionscore sum = 1862vs. 1743). Especially in the cervical spine, the spinal movement was reduced (motionscore sum = 339 vs. 595). However, the thoracic spine movement was increased (motionscore sum = 812 vs. 432).

Conclusion: In case of a suspected cervical spine injury, guided self-extrication seems to be the best option. If the patient is not able to perform self-extrication, using a rescue boa might reduce cervical spinal movement compared to the traditional extrication procedure. Since promising results are shown in the case of extrication using a patient transfer sheet that has already been placed below the driver, future developments should focus on novel vehicle seats that already include an extrication device.